pyroclastic

American  

[pahy-ruh-klas-tik] / ˌpaɪ rəˈklæs tɪk /

adjective

Geology.

1. composed chiefly of fragments of volcanic origin, as agglomerate, tuff, and certain other rocks; volcaniclastic.

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pyroclastic British  

/ ˌpaɪrəʊˈklæstɪk /

adjective

1. (of rocks) formed from the solid fragments ejected during a volcanic eruption

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pyroclastic Scientific  

/ pī′rō-klăs′tĭk /

1. Composed chiefly of rock fragments of explosive origin, especially those associated with explosive volcanic eruptions. Volcanic ash, obsidian, and pumice are examples of pyroclastic materials.

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Etymology

Origin of pyroclastic

First recorded in 1885–90; pyro- + clastic

Example Sentences

The rise and collapse of the eruption column presaged a series of pyroclastic surges, the fourth of which killed everyone in its path in Pompeii.

From The Wall Street Journal • Jan. 2, 2026

The temperature of the pyroclastic flows that buried Herculaneum and Pompeii was several hundreds of degrees Celsius, hot enough to easily burn and destroy soft tissue.

From Salon • Mar. 4, 2025

Experts believe the ash cloud turned the man's brain into glass because the pyroclastic flow would not have reached high enough temperatures or cooled quickly enough.

From BBC • Feb. 27, 2025

The sulfate deposit, made mainly of jarosite, a hydrous sulfate, was interpreted to have formed when the blanket of volcanic pyroclastic materials came to rest on a glacier and reacted chemically with the ice.

From Science Daily • Mar. 13, 2024

However, the heat of the pyroclastic flow at noon melted several glaciers and significantly added to the flow of water and mud that had begun earlier in the day.

From "Mountain of Fire" by Rebecca E. F. Barone